JPS5855936B2 - brake pedal assembly - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a brake pedal assembly for providing actuation input to a master cylinder to apply brakes.

In most automobile brake systems, some amount of free movement occurs when the brake shoes or brake pads are engaged and moved onto the brake drum or rotor.

The travel of the brake pedal required to actuate the brake system is one-third of the total travel of the brake pedal.

the toggle link device disclosed in U.S. Pat. No. 3,142,199; the lever and diaphragm structure disclosed in U.S. Pat. No. 3,263,428;
the slotted lever disclosed in U.S. Pat. No. 3,063,427; the resiliently positioned lever disclosed in U.S. Pat. No. 3,633,366; and the resiliently positioned lever disclosed in U.S. Pat. Brake pedal linkages have been developed that vary the ratio of travel of the output push rod relative to the brake pedal, such as the lever and cam structure disclosed in the '831 patent.

A disadvantage of many of these conventional brake pedals is that they require a large number of interacting parts to effect a change in the movement of the output push rod relative to the input movement of the brake pedal.

This increases the height of the brake pedal relative to the vehicle floor, making it difficult to simply rotate the foot from the gas pedal to the brake pedal as most drivers experience in vehicles manufactured today. Rather, the driver is required to move the brake pedal by lifting his foot at a different height than the gas pedal.

Therefore, it is an object of the present invention to change the constant velocity movement of the brake pedal so that the push rod is rapidly moved by the lever that activates the braking device, and the push rod is moved at a constant speed to move the brake pedal. It is an object of the present invention to provide a brake device with a brake pedal assembly configured to generate a final output corresponding to an optimal force combined with a brake pedal assembly and requiring fewer parts than conventional structures.

Another object of the present invention is to provide a brake pedal assembly configured such that the height of the brake pedal relative to the floor of a vehicle is approximately equal to the height of the accelerator pedal.

According to the principles of the invention, the above objects include: a stationary housing; an input lever having a first end pivotally connected to the housing and a second end having a brake pedal fixed thereto; A plate that is pivotally connected and has a cam surface, and a plate that is pivotally attached to the same plate,
The output push rod connected to the master cylinder and the above--
a pin fixed to the housing and permanently engaged with the cam surface, the cam surface sliding against the pin when the lever is moved to rotate the plate on the lever and push the push rod. and a circular portion for moving the push rod at a faster speed than the movement of the lever when the lever first moves from the rest position, and a circular portion for moving the push rod at a faster speed than the movement of the lever when the lever is moved further from the rest position. This is accomplished by a brake pedal assembly characterized in that it includes a curved portion that moves at a speed substantially equal to the movement of the brake pedal.

This linear movement of the push rod is therefore caused by a combination of an arcuate movement about the pivot joint of the brake pedal lever and a rotational movement of the plate on the brake pedal lever due to the engagement of the cam surface and the fixing pin.

In a preferred embodiment of the invention, the cam surface of the plate engages the fixed pin via a roller mounted on the pin to reduce sliding friction therebetween.

These and other features and advantages of the invention will become apparent from the following description of a preferred embodiment with reference to the grading drawings.

In the brake system shown in FIG. 1, the master cylinder 12 is connected to the vehicle's front and rear brakes 14 and 16
is connected to.

Master cylinder 12 provides fluid pressure to front and rear brakes 14 and 16 for braking application in response to driver input applied to brake pedal assembly 18 .

Brake pedal assembly 18 includes - housing or suspension member 2
0, the housing is located between the dash board and the firewall of the vehicle to position the input brake lever 22 within the driver's cab.

The brake lever is a pin 26 fixed to the housing 20.
It has a first end 24 and a second end 28 pivoted thereon.

A brake pedal or pad 30 attached to the second end 28 provides for the driver to apply input to move the brake lever 22 in an arc about the pin 26.

The brake lever 22 has a projection 32 with a support surface for mounting a pin 34.

A plate 36 pivotally mounted on the pin 34 has a pin 38 fixed at its end, as shown in FIG. .

The plate 36 has a cam surface with a first portion 44 having a circular curve, a second curved portion 46 having a spiral curve, and a third portion 48 for transitioning the circular curve to a spiral curve.

The cam surface on the plate 36 is moved by the reaction force or return force within the master cylinder 12 acting on the push rod 42.
It is held against a roller 50 mounted on a pin 52 fixed to.

When the driver of the vehicle wishes to apply the brakes, input can be applied to pad 30 by the driver removing his foot from accelerator pedal 59 and rotating it.

The input applied to hat 30 then causes brake lever 22 to rotate through an arc about pin 26.

This input corresponds to pin 26 for the distance between pins 26 and 34.
and the end 28.

The modified human power is transmitted to the plate 36 via the pin 34 and distributed to the push rod 42 via the pin 38.

When brake lever 22 is moved from the rest position shown in FIG. let

The rotation of this plate when combined with the arcuate movement of the brake lever is adapted to impart linear movement to the push rod 42.

In order to evaluate the change in the linear movement of the push rod 42 with respect to the arc movement of the brake lever 22, the arc movement stroke of the brake lever is divided into equal line segments, and the distance traveled by the push rod 42 in each line segment is plotted as a point. A curve 60 in Figure 3 is obtained.

Comparing curve 60 to curve 62, which shows the movement of a push rod affixed directly to the brake lever, it is noted that push rod 42 initially moves at a faster speed than brake lever 22.

This is a desirable feature that allows the actuating piston in the master cylinder 12 to pass through the fill port in the master cylinder and begin supplying the wheel brakes 14 and 16 with brake fluid at a relatively low pressure. A small movement of the brake lever is sufficient to engage the brake lever with the rotor and the brake shoe with the drum.

On subsequent button presses, as the brake lever 22 travels the remaining arc of its travel about the pin 26, the roller 50 passes through the transition portion 48 of the cam surface and follows the curved portion 46.

Rotation of the plate 360 by the curved portion 46 causes the push rod 42 to be moved by the pin 38 a distance approximately equal to the distance between each movement of the brake lever 220.

When the brake lever 22 moves through its entire travel, the movement of the push rod 42 is equal to the total movement that would occur if the push rod was fixed to the brake lever.

When the operator ceases inputting the pad 30, the return spring within the master cylinder 12 moves the push rod 42 toward the rest position shown in FIG.

The push rod 42 moves to push the circular portion 44 of the cam surface onto the roller 5.
0, the rearward movement of the brake lever 22 is stopped and the brake lever is held in a rest position where the pad 30 and the accelerator pedal 59 are substantially flush with the driver's feet.

[Brief explanation of the drawing]

1 is a schematic illustration of a brake system including a brake pedal assembly constructed in accordance with the principles of the present invention; FIG. 2 is a cross-sectional view taken along line 2--2 of FIG. 1; and FIG. FIG. 2 is a chart showing the linear output movement of a push rod connected to a master cylinder of a brake device against circular movement; FIG. In the drawing, 12 is a master cylinder, 14 is a front wheel brake, 16 is a rear wheel brake, 18 is a brake pedal assembly, 20 is a nozzle, 22 is a brake lever,
26, 34, 38, 52 are pins, 30 is a pad, 36 is a plate, 42 is a push rod, 44° 46.48 is a cam surface part,
50 indicates a roller, and 59 indicates an accelerator pedal.

Claims (1)

[Scope of Claims] 1. A stationary housing 20, an input lever 22 whose first end is pivotally connected to the housing and whose second end has a brake pedal 30 fixed to the housing; a plate 36 which is pivotally attached to the housing and has a cam surface; an output push rod 42 which is pivotally attached to the plate and connected to the master cylinder 12; The cam surface includes a pin 52, and when the lever is moved, the plate is rotated on the lever relative to the pin to move the push rod, and when the lever is moved, the push rod is moved from the rest position. a circular portion 44 for moving the push rod at a speed faster than the movement of the lever when the lever moves further; and a circular portion 44 that moves the push rod at a speed substantially equal to the movement of the lever when the lever moves further; A brake pedal assembly comprising: a curved portion 46 for causing the brake pedal to rotate; 2 a transition section 4 in which the cam surface of said plate 36 provides a smooth intermediate surface between said circular section 44 and said curved section 46;
8. The brake pedal assembly of claim 1, further comprising: 8. 3. The cam surface of the plate 36 engages with the fixing pin 52 via a roller 50 mounted on the pin to reduce sliding friction therebetween. A brake pedal assembly according to scope 1 or 2.